There are a number of devices available and especially adapted for bending pipe, tubing, and other forms of metal stock. Some of these devices are hand tools that may be manually operated to impart a bend on the stock to thereby place the stock in a desired shape and configuration. There are also a number of devices that are designed for bending more substantial pieces of stock and therefore, are table mounted or mounted to a fairly large base. These latter type of devices may be power assisted or power operated.
One example of a bending apparatus that is hand operated includes the apparatus disclosed in U.S. Pat. No. 4,167,865. This apparatus includes a base, a clamp on the base for holding portions of the metal stock to be shaped, and an elongate handle that is pivotably carried on the base and which can swivel about an axis. The handle carries a spring biased slide member having a pin constituting a shoulder adapted for engagement with the metal stock. The clamp is in the form of a vice having a fixed jaw constituted as a die, around which the metal stock is formed. The slide member is normally biased toward the pivotal axis of the handle but can yield outwardly in a direction away from such axis as the handle is swivelled. The yieldable shoulder on the handle permits the use of dies having irregular shapes.
One example of a pipe bending apparatus that is power operated for forming more substantial pieces of stock includes the apparatus disclosed in the U.S. Pat. No. 6,192,728. The device disclosed here includes a base, a material feeding device fixed on the base, an arm turning shaft fixed in front of the base, a bending mold fixed on the arm turning shaft, and a turning arm rotated by a transmitting device. The turning arm has a clamp mold fixed thereon for clamping a material pipe with help of the bending mold. The transmitting device includes a threaded rod rotated by a motor, a threaded nut mounted on the threaded rod and connected with a pull block, and an interactive device positioned between the pull block and arm turning shaft. Rotation force of the motor is converted into a linear force by means of the threaded rod and nut.
Another common type of bending device is shown in the U.S. Pat. No. 5,148,695. In this reference, the bending device is mounted on a stand or base, and the bending apparatus can be disassembled and moved to a different work site. However, even with pipe bending devices similar to the one described in this reference, such devices still require substantial effort in assembly and disassembly.
While the above described devices may be adequate for their intended purposes, there is still a need for a simple yet effective bending apparatus that is easily transportable and may be manually operated. In the construction of many commercial buildings and most homes, the great majority of piping systems installed include stock that may be bent by a hand operated bending device. Accordingly, the most common device used by pipefitters is still a hand operated pipe bender.